This invention relates generally to interlocking laminations used in electrical devices, such as those used in the windings for D.C. motor armatures or A.C. rotors and stators.
Typically, laminations are stacked, or piled together to achieve a required thickness of laminations. Because the laminations undergo further processing, such as being wound to form a motor core, it is desirable to retain the laminations together in a stack of a desired height so that the stack of laminations can be moved together to a subsequent manufacturing process.
Various methods and apparatuses have been used to fasten laminations together, including the use of tabs in the laminations which extend below the lower surface of the lamination and are inserted into a slot formed in a next adjacent lamination. Typically, the lowest lamination in the stack has the interlock tabs removed because there is no need to secure the lowest lamination in the stack to anything else.
A drawback with the foregoing method of securing laminations together is that sometimes, in the course of further processing of the laminations, a lamination may come out of the slot on the next lower lamination. When this happens, the integrity of the stack is lost, and production must be stopped to realign the stack, or the part must be rejected. In one attempt to resolve this drawback, a wrapper of some sort is placed around the stack of laminations, but because the stack of laminations undergoes further processing, such as winding, such a wrapper may interfere with the additional processing. Also, because these stacks of laminations are used in electrical equipment, care must be taken that the material of any such wrapper does not interfere with the electrical and magnetic properties of the laminations.
Accordingly, a continuing search has been directed to the development of a system and method by which laminations in a stack may be more securely interlocked to each other without decreasing the throughput of lamination stacks, and without affecting the electrical and magnetic properties of the resultant stack of laminations.